In a heavy bottom stock pot, caramelize the sugar over medium heat until it forms large breaking bubbles. Deglaze with the balsamic vinegar and port and reduce the liquids by 1/3. Add the cranberries and cook until soft and the mixture reaches a jam-like texture. Add the stock and seasonings and reduce the liquid by 1/2, or until the sauce coats the back of a wooden spoon. Strain the mixture and adjust the seasonings with sea salt and white pepper.
Serving ideas: we serve this with pan-roasted duck breast or grilled pork tenderloin.